Saliva pornography involves salivation and saliva. Teacher and Student or Boss and Secretary pornography involves sexualized situations which take place between an authority figure, such as a teacher or boss, and an underling, such as a student or secretary, often fake. While bondage is a very popular variation within the larger field of BDSM, it is nevertheless sometimes differentiated from the rest of this field. As in B/D, the declaration of the Top/Bottom may be required, though sadomasochists may also play without any Power Exchange at all, with both partners equally in control of the play. Clothed female, naked male is a genre of erotica featuring one or more nude men and one or more clothed women. When questioned about her particular kink Covét gay sex replied, If we women have to take it from behind, then why not a man? Now facial cumshots are regularly portrayed in pornographic films, videos, magazines and internet web sites. Sadomasochism does not imply enjoyment through causing or receiving pain in other situations . In pornography, depictions of lesbian sex form a popular subgenre, directed toward a male heterosexual and female homosexual audience. The Japanese sex industry uses the term Paizuri . The speed of the hand motion will vary from person to person, although it is not uncommon for the speed to increase as ejaculation nears and for it to decrease during the ejaculation itself. In the 1970s, the hardcore pornography genre introduced the stereotypical cumshot scene as a central element of the hardcore film, in which the male actor ejaculates in a way ensuring maximum visibility of the act itself. It may also involve touching, rubbing, or pinching the nipples or other erogenous zones while masturbating. Rape itself is a crime in many countries. Men and women may masturbate until they are close to orgasm, stop for a while to reduce excitement, and then resume masturbating. Japanese rope bondage is distinguished by its use of specific katas and aesthetic rules.